64535821 has 16 divisors (see below), whose sum is σ = 75613824. Its totient is φ = 53936064.

The previous prime is 64535803. The next prime is 64535833. The reversal of 64535821 is 12853546.

It is not a de Polignac number, because 64535821 - 2⁷ = 64535693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64532821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 72646 + ... + 73528.

It is an arithmetic number, because the mean of its divisors is an integer number (4725864).

Almost surely, 2^64535821 is an apocalyptic number.

It is an amenable number.

64535821 is a deficient number, since it is larger than the sum of its proper divisors (11078003).

64535821 is a wasteful number, since it uses less digits than its factorization.

64535821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1140.

The product of its digits is 28800, while the sum is 34.

The square root of 64535821 is about 8033.4190106081. The cubic root of 64535821 is about 401.1131928801.

It can be divided in two parts, 64535 and 821, that added together give a palindrome (65356).

The spelling of 64535821 in words is "sixty-four million, five hundred thirty-five thousand, eight hundred twenty-one".